mcs/class/System.Web/System.Web.SessionState_2.0/RemoteStateServer.cs

   1 //
   2 // System.Web.SessionState.RemoteStateServer
   3 //
   4 // Author(s):
   5 //  Jackson Harper (jackson@ximian.com)
   6 //  Gonzalo Paniagua (gonzalo@ximian.com)
   7 //  Marek Habersack (grendello@gmail.com)
   8 //
   9 // (C) 2003-2006 Novell, Inc (http://www.novell.com)
  10 //
  11
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32 #if NET_2_0
  33 using System;
  34 using System.Threading;
  35 using System.Web.Caching;
  36
  37 namespace System.Web.SessionState {
  38         class LockableStateServerItem
  39         {
  40                 public StateServerItem item;
  41                 public ReaderWriterLock rwlock;
  42
  43                 public LockableStateServerItem (StateServerItem item)
  44                 {
  45                         this.item = item;
  46                         this.rwlock = new ReaderWriterLock ();
  47                 }
  48         }
  49
  50         internal class RemoteStateServer : MarshalByRefObject {
  51                 const Int32 lockAcquireTimeout = 30000;
  52                 Cache cache;
  53
  54                 internal RemoteStateServer ()
  55                 {
  56                         cache = new Cache ();
  57                 }
  58
  59                 void Insert (string id, LockableStateServerItem item)
  60                 {
  61                         cache.Insert (id, item, null, Cache.NoAbsoluteExpiration, new TimeSpan (0, item.item.Timeout, 0));
  62                 }
  63
  64                 LockableStateServerItem Retrieve (string id)
  65                 {
  66                         return cache [id] as LockableStateServerItem;
  67                 }
  68
  69                 internal void CreateUninitializedItem (string id, int timeout)
  70                 {
  71                         StateServerItem item = new StateServerItem (timeout);
  72                         item.Action = SessionStateActions.InitializeItem;
  73                         LockableStateServerItem cacheItem = new LockableStateServerItem (item);
  74                         Insert (id, cacheItem);
  75                 }
  76
  77                 internal StateServerItem GetItem (string id,
  78                                                   out bool locked,
  79                                                   out TimeSpan lockAge,
  80                                                   out object lockId,
  81                                                   out SessionStateActions actions,
  82                                                   bool exclusive)
  83                 {
  84                         Console.WriteLine ("RemoteStateServer.GetItem");
  85                         Console.WriteLine ("\tid == {0}", id);
  86                         locked = false;
  87                         lockAge = TimeSpan.MinValue;
  88                         lockId = Int32.MinValue;
  89                         actions = SessionStateActions.None;
  90
  91                         LockableStateServerItem item = Retrieve (id);
  92                         if (item == null || item.item.IsAbandoned ()) {
  93                                 Console.WriteLine ("\tNo item for that id (abandoned == {0})", item != null ? item.item.IsAbandoned() : false);
  94                                 return null;
  95                         }
  96
  97                         try {
  98                                 Console.WriteLine ("\tacquiring reader lock");
  99                                 item.rwlock.AcquireReaderLock (lockAcquireTimeout);
 100                                 if (item.item.Locked) {
 101                                         Console.WriteLine ("\titem is locked");
 102                                         locked = true;
 103                                         lockAge = DateTime.UtcNow.Subtract (item.item.LockedTime);
 104                                         lockId = item.item.LockId;
 105                                         return null;
 106                                 }
 107                                 Console.WriteLine ("\teleasing reader lock");
 108                                 item.rwlock.ReleaseReaderLock ();
 109                                 if (exclusive) {
 110                                         Console.WriteLine ("\tacquiring writer lock");
 111                                         item.rwlock.AcquireWriterLock (lockAcquireTimeout);
 112                                         Console.WriteLine ("\tlocking the item");
 113                                         item.item.Locked = true;
 114                                         item.item.LockedTime = DateTime.UtcNow;
 115                                         item.item.LockId++;
 116                                         Console.WriteLine ("\tnew lock id == {0}", item.item.LockId);
 117                                         lockId = item.item.LockId;
 118                                 }
 119                         } catch {
 120                                 throw;
 121                         } finally {
 122                                 if (item.rwlock.IsReaderLockHeld) {
 123                                         Console.WriteLine ("\treleasing reader lock [finally]");
 124                                         item.rwlock.ReleaseReaderLock ();
 125                                 }
 126                                 if (item.rwlock.IsWriterLockHeld) {
 127                                         Console.WriteLine ("\treleasing writer lock [finally]");
 128                                         item.rwlock.ReleaseWriterLock ();
 129                                 }
 130                         }
 131
 132                         Console.WriteLine ("\treturning an item");
 133                         actions = item.item.Action;
 134                         return item.item;
 135                 }
 136
 137                 internal void Remove (string id, object lockid)
 138                 {
 139                         cache.Remove (id);
 140                 }
 141
 142                 internal void ResetItemTimeout (string id)
 143                 {
 144                         LockableStateServerItem item = Retrieve (id);
 145                         if (item == null)
 146                                 return;
 147                         item.item.Touch ();
 148                 }
 149
 150                 internal void ReleaseItemExclusive (string id, object lockId)
 151                 {
 152                         LockableStateServerItem item = Retrieve (id);
 153                         if (item == null || item.item.LockId != (Int32)lockId)
 154                                 return;
 155
 156                         try {
 157                                 item.rwlock.AcquireWriterLock (lockAcquireTimeout);
 158                                 item.item.Locked = false;
 159                         } catch {
 160                                 throw;
 161                         } finally {
 162                                 if (item.rwlock.IsWriterLockHeld)
 163                                         item.rwlock.ReleaseWriterLock ();
 164                         }
 165                 }
 166
 167                 internal void SetAndReleaseItemExclusive (string id, byte [] collection_data, byte [] sobjs_data,
 168                                                           object lockId, int timeout, bool newItem)
 169                 {
 170                         Console.WriteLine ("RemoteStateServer.SetAndReleaseItemExclusive");
 171                         Console.WriteLine ("\tid == {0}", id);
 172                         LockableStateServerItem item = Retrieve (id);
 173                         bool fresh = false;
 174
 175                         if (newItem || item == null) {
 176                                 Console.WriteLine ("\tnew item");
 177                                 item = new LockableStateServerItem (new StateServerItem (collection_data, sobjs_data, timeout));
 178                                 item.item.LockId = (Int32)lockId;
 179                                 fresh = true;
 180                         } else {
 181                                 if (item.item.LockId != (Int32)lockId) {
 182                                         Console.WriteLine ("\tLockId mismatch ({0} != {1})", item.item.LockId, lockId);
 183                                         return;
 184                                 }
 185                                 Console.WriteLine ("\tremoving from cache");
 186                                 Remove (id, lockId);
 187                         }
 188
 189                         try {
 190                                 Console.WriteLine ("\tacquiring writer lock");
 191                                 item.rwlock.AcquireWriterLock (lockAcquireTimeout);
 192                                 item.item.Locked = false;
 193                                 if (!fresh) {
 194                                         Console.WriteLine ("\tnot fresh = updating data");
 195                                         item.item.CollectionData = collection_data;
 196                                         item.item.StaticObjectsData = sobjs_data;
 197                                 }
 198                                 Console.WriteLine ("\tInserting in cache");
 199                                 Insert (id, item);
 200                         } catch {
 201                                 throw;
 202                         } finally {
 203                                 if (item.rwlock.IsWriterLockHeld) {
 204                                         Console.WriteLine ("\treleasing writer lock [finally]");
 205                                         item.rwlock.ReleaseWriterLock ();
 206                                 }
 207                         }
 208                 }
 209
 210                 public override object InitializeLifetimeService ()
 211                 {
 212                         return null; // just in case...
 213                 }
 214         }
 215 }
 216 #endif